1. Field of the Invention
The present invention relates to an image processing method and an apparatus. More particularly, the present invention relates to an image brightness controlling method and apparatus for a display apparatus to enhance image brightness and maintain image hue and saturation.
2. Description of Related Art
If flat panels are used in color display apparatus or color TV sets, the size thereof could be increased. However, as compared with CRT (cathode ray tubes)-type display apparatus, the image brightness of flat panel display apparatus is reduced. In order to overcome disadvantages, a four color component display apparatus based on three base color component signals (red, green, blue) and a white component signal can be used. In order to obtain the white component signal, a white light is passed through or reflected from a white filter, thereby enhancing overall image brightness.
However, according to this technique, it is difficult to maintain the hue and saturation of the original input image signal, because ratio relationship of three base color component signals of the original input image signal is not maintained.
Adding the white component signal to the original three base color component signals to enhance the image brightness will negatively cause the decrease of saturation. In order to overcome the negative effect, it is necessary to adjust the original three base color component signals, so that when the adjusted three color component signals and the white component signal are output or display together, the brightness can still be enhanced and the saturation remains unchanged.